| (19) |
 |
|
(11) |
EP 0 893 431 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
24.03.1999 Bulletin 1999/12 |
| (43) |
Date of publication A2: |
|
27.01.1999 Bulletin 1999/04 |
| (22) |
Date of filing: 10.07.1998 |
|
|
| (84) |
Designated Contracting States: |
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AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
Designated Extension States: |
|
AL LT LV MK RO SI |
| (30) |
Priority: |
14.07.1997 IT TO970636
|
| (71) |
Applicant: FINCHIMICA S.p.A. |
|
25025 Manerbio (Brescia) (IT) |
|
| (72) |
Inventor: |
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- Bernardi, Gianluca
25133 Brescia (IT)
|
| (74) |
Representative: Rambelli, Paolo et al |
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c/o JACOBACCI & PERANI S.p.A.
Corso Regio Parco, 27
10152 Torino
10152 Torino (IT) |
|
| |
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| (54) |
A method for the purification of dinitroanilines |
(57) A method for the purification of dinitroanilines having herbicidal activity by means
of the known reactions of denitrosation using acid, and denitration in a neutral or
basic environment in the presence of a phase-transfer catalyst, characterised in that:
- the denitrosation reaction is effected on the dinitration mixture containing the dinitroaniline
of interest and the corresponding unwanted N-nitroso- and N-dinitroaniline impurities,
and in the absence of solvent,
- the denitration reaction is conducted sequentially to the denitrosation reaction in
the same reactor with the addition to the denitrosation product as such of an aqueous
base, and of the said phase-transfer catalyst.